AB1228 RADIOFREQUENCY ECHOGRAPHIC MULTISPECTROMETRY COMPARED WITH DUAL X-RAY ABSORPTIOMETRY FOR OSTEOPOROSIS DIAGNOSIS ON LUMBAR SPINE AND FEMORAL NECK IN A COLOMBIAN POPULATION
Authors: E. Jauregui, K. Gonzalez, M. Nuñez, J. Londoño, B. Corredor, J. Huertas, C. Cabrera
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> An innovative non-ionizing ultrasound technique for osteoporosis diagnosis, which directly measures the BMD (Bone Mineral Density) of both the lumbar spine and the femoral neck, REMS, has shown significant correlations with BMD values and good levels of concordance with DXA-based diagnoses. <h3>Objectives</h3> Cross-sectional study to establish the concordance of BMD measurement between REMS and the gold standard (DXA) in Colombian adult patients receiving oral steroids. <h3>Methods</h3> Observational, analytical and descriptive, cross-sectional study in adults of both sexes who receive steroids and who attend a rheumatology center in Bogotá-Colombia. Inclusion criteria: Men and women over 18 years. Receiving steroids more than 2.5 mg of prednisone or its equivalent for 3 or more continuous months. Interpretable bone densitometry. Subjects who accepted their participation in the study and signed the informed consent. Exclusion criteria: History of prosthesis implantation in the abdomen and/or buttocks. Known physical deformities and/or previous lumbar spine surgery and/or bilateral hip replacement. Pregnant women. Subjects prevented from performing bone densitometry. The densitometric measurements were made with a compact high-performance equipment from General Electric, model iDXA, by the same technologist at the skeletal sites of interest. In a second moment, the same trained technologist performed the BMD measurement with REMS, using an EchoS machine (Echolight®), equipped with a 3.5 MHz convex transducer. This study was submitted and approved by the institutional ethics committee. The calculation of the sample size was carried out with the prevalence of osteoporosis induced by steroids, for n of 185 individuals. The concordance between the two technologies was evaluated with the weighted Cohen's Kappa index. <h3>Results</h3> 200 patients were included in the study, 162 were women. The median age of the entire cohort was 50.5 years (IQR: 22.2), with a minimum age of 20 and a maximum of 86 years. In women, the median age at menarche was 13 years (IQR: 2) and the median age for menopause was 47 years (IQR: 8), only 2.50% (n = 5) reported having fractures for fragility. 51% of the patients had rheumatoid arthritis, SLE 29% and other diagnoses 20%. Regarding the type of corticosteroid used, 92.5% received prednisolone. The last dose of corticosteroid used in median was 5 mg/day (IQR: 5). In the case of the accumulated dose in the last year, the median was 1825 mg/year (IQR: 1850). For the concordance analysis, 11 patients were excluded because the image of all the lumbar vertebral bodies could not be interpreted with both DXA and REMS techniques. Taking into account the diagnostic classification of each technology, a diagnostic concordance was obtained with the weighted Cohen's Kappa index of κ ω= 0.72 95%CI: [0.63; 0.81] in the lumbar spine and κ ω= 0.65 95% CI: [0.54; 0.74] in femoral neck. <h3>Conclusion</h3> In Colombian patients receiving steroids, the diagnostic concordance for BMD measurement between DXA and REMS is good; however, there are factors that affect the measurement, for which further training in REMS is required for the technologist to mitigate errors and improve the concordance between the techniques. <h3>REFERENCES:</h3> NIL. <h3>Acknowledgements:</h3> NIL. <h3>Disclosure of Interests</h3> Edwin Jauregui Speakers bureau: Abbvie, Biopas, Amgen, Fresenius kabi, Consultant of: Abbvie, Amgen, Grant/research support from: Bristol myers Squibb, Katherine Gonzalez: None declared, Marcela Nuñez: None declared, Juan Londoño: None declared, Bibiana Corredor: None declared, Juan Huertas: None declared, Catalina Cabrera: None declared.